Renewable Energy Sources (RES), despite their clear advantages over fossil fuel derived energy, are still a relatively small proportion of the total energy used. Furthermore, they are usually far more expensive then their comparable fossil counterparts, in a cost per kWh base. Hence it is fair to say that RES still need considerable development efforts if they are to become a viable and applicable alternative to energy derived from fossil fuel.
In order to fulfill these goals, one should not only consider currently available developed technologies, based on a concept dating back to medieval wind mills in the case of energy production through wind power utilization, but also strive forward with radically new ways of harnessing the wind's energy, which is the intention of this invention.
In the case of harnessing wind power, this problem is further enlarged due to the currently used philosophy of power production: operating essentially as wind mills of the past, the latest generation of turbines continues to explore wind at very low altitudes. It is known that wind speeds (and its power density) increase with altitude, although this relationship is not linear. If we continue to operate at low altitudes, we are forced to see wind energy as an essentially scarce resource, offering energy densities per unit of area inferior to those of solar power. In this case in order to be cost competitive we would need to maximize the efficiency of the current wind turbines. This efficiency maximization can be very expensive, yielding a cost per unit of power produced higher than other competitive energy forms.
The present invention, developed in the field of mechanical engineering, proposes a different approach to wind energy conversion and to the harness of wind power, with a clear focus on decreasing the inherent costs of this energy source. Instead of maximizing the efficiency of currently available wind turbines, a system is conceived where the cost per unit of power output from wind power is not only much lower, but also far less dependent upon the conversion efficiency of the system, when compared with wind turbines.
It is also considered that the present system can solve the open question of high altitude platforms, which has not yet seen the desired technological breakthrough. All solutions proposed so far are always short on the energy supply system, due essentially to the storage issue. This shortage hinders the platform's ability to remain airborne for considerable periods of time, in the case of heavier than air systems (aircrafts or airplanes), but also poses major problems for lighter-than-air crafts (e.g. aerostats and balloons) since the energy requirements for allowing control are usually above the energy storage capacity installed. In this latter case the lighter-than-air crafts will not have sufficient power for pitch and attack angle control, frequently being adrift in the wind, in situations where the drag can become unsustainable. With respect to airplanes, attempts have been made to use solar power as an energy source, but night time operation remains a major unsolved problem. Wind power, available also during night periods, provides a more interesting and viable option.
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